World No.2 Angelique Kerber has gotten her Sydney International defence off to a strong start after outlasting Camila Giorgi 7-6 (7-3) 6-2.

The German was forced to draw on all her experience when Giorgi pushed her all the way to a tiebreaker on Ken Rosewall Arena on Tuesday, but was thoroughly outplayed thereafter.

Kerber, who enjoyed a bye in the first round, advances straight to a quarter-final against either fifth-seed Petra Kvitova or Hsieh Su-Wei.